Powertrain Controls - ECM/PCM

DTC 75 System Voltage Low:

System Voltage:

CIRCUIT DESCRIPTION
Ignition voltage is supplied to the control module indicate the ignition status of the ignition switch. Battery voltage is supplied to the control module to, in part, maintain memory of learned functions and parameters.

DTC 75 WILL SET WHEN:
^ The ignition is "ON."
^ Ignition feed voltage to the control module is less than the graduated scale of:
- -40°C (-40°F) = 7.3 volts.
- 90°C (194°F) = 10.3 volts.
- 150°C (304°F) = 11.7 volts.
^ Engine speed greater than 1000 RPM.
^ All conditions met for 4 seconds.

ACTION TAKEN (TCM will default to)
^ Maximum line pressure.
^ 2nd gear (4L80E), 3rd gear (4L60E).
^ Inhibit Torque Converter Clutch (TCC).
^ Inhibit 4th gear.

DTC 75 WILL CLEAR WHEN
The fault condition(s) no longer exist, and the ignition switch is cycled "OFF" then "ON."

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks for normal battery voltage between 9-15 volts.
2. This test checks if the generator is faulty under load conditions. If the voltage is greater than 15 volts, refer to Charging System.

DIAGNOSTIC AIDS
Charging the battery and jump-starting an engine may set DTC 52/DTC 53. If DTC(s) sets when an accessory is operated, check for faulty connections or excessive current draw. Refer to Charging System for circuit details.
Check for poor connections at starter solenoid or fusible link.